The following electric stapler is well known. Connected staples, in which a large number of straight staple materials are aligned and bonded to each other so that they can be formed into a sheet-shape, are charged into an cartridge. The cartridge is attached into a magazine of the electric stapler. The connected staples are successively supplied from the cartridge to a drive section provided in the forward end portion of the magazine. A lead staple of these connected staples is formed into a U-shape by a forming plate in a drive section. The U-shaped staple is supplied to a drive passage formed in the drive section. The staple is driven from the drive passage by a driver plate sliding in the drive passage, so that legs of the staple are made to penetrate sheets of paper to be stapled arranged below the drive section of the magazine. The legs of the staple, which have penetrated the sheets of paper to be stapled, are bent along the reverse side of the sheets of paper to be stapled by a clincher mechanism arranged below the magazine. Due to the foregoing, the sheets of paper are stapled by the electric stapler.
The magazine of the above electric stapler includes: a drive section, which forms a drive passage for guiding the staple to sheets of paper to be stapled, provided at the forward end portion of the magazine; a staple supply mechanism which supplies the staple charged in the cartridge toward the drive section; and a forming and driving mechanism which forms the staple supplied to the drive section into a U-shape and drives the staple from the drive passage toward the sheets of paper to be stapled, wherein the magazine is arranged being isolated from the clincher mechanism, which bends legs of the staple when the stapler is not operated, by a predetermined space in which the sheets of paper to be staples are arranged. When the electric stapler is operated in order to staple the sheets of paper to be stapled which are arranged in the above space, the magazine is operated in the direction of the clincher mechanism so as to clamp the sheets of paper between the magazine and the clincher mechanism. After that, the forming and driving mechanism of the magazine section is operated so that the staple can be driven to the sheets of paper to be stapled. The magazine of the electric stapler is composed as described above.
The forming and driving mechanism of the magazine of the electric stapler includes: a forming plate for forming a straight staple material of the connected staples, which is supplied to the drive section, into a U-shape; and a driver plate for driving the staple, which has been formed into the U-shape, toward the sheets of paper to be stapled, wherein the driver plate is slidably provided being opposed to the drive passage of the drive section. The forming and driving mechanism is slid in the direction of the clincher mechanism section by a rotary member, which is rotated by an electric motor, via a link member engaged with a cam groove formed in the rotary member. Due to the foregoing, the staple material is formed into a U-shape and driven out from the drive passage. When the forming and driving mechanism held by the magazine is driven in the direction of the clinch mechanism, the magazine is operated in the direction of the clincher mechanism by a sliding resistance between the forming and driving mechanism and the magazine while the magazine is following the forming and driving mechanism.
In the conventional electric stapler, the rear end portion of the magazine is pivotally supported by a rotary support shaft inside the support frame, and the magazine section is driven by the sliding resistance with the forming plate and the driver plate which are driven for driving out the staples provided in the magazine. Therefore, when the rotary resistance of the magazine is increased by the abrasion and deformation caused while the electric stapler is being used, it becomes difficult for the magazine to be rotated and the staple is driven out from the magazine section to the sheets of paper to be stapled by the driver plate before the lower face of the magazine is tightly contacted with the sheets of paper to be stapled. In this state, no guide is provided for guiding the staple legs between the surface of the sheets of paper to be stapled and the drive passage of the staples. Therefore, buckling is generated in the staple legs and failure in stapling is caused.
When the magazine is operated by an elastic force of the compression spring provided between the link, which drives the driver plate, and the magazine as described in JP-Y-06-007896, even if the operational resistance of the magazine is increased a little, the magazine can be operated before the staple is driven out by the driver plate. However, in this electric stapler, the magazine of which is vertically operated with respect to the surface of the sheets of paper to be stapled so that the electric stapler can cope with fluctuation of the thickness of the sheets of paper to be stapled, the sliding resistance generated between the support frame, which slidably supports the magazine, and the magazine, is increased. Therefore, in order to positively operate the magazine by the compression spring, it is necessary to set the elastic force of the compression spring at a high value. Therefore, the forming plate and the driver plate must be operated overcoming the spring force of this high value, which increases a load given to the drive motor. Accordingly, a large drive motor is required and a drive current to drive the motor is increased, which makes it impossible to save electric power.